A region of central Europe primarily in southwest Poland and the northern Czech Republic. Settled by Slavic peoples c. ad 500, the region was long contested by various states and principalities. After World War I Silesia was partitioned among Germany, Poland, and Czechoslovakia. Much of the Czechoslovakian section passed to Germany and Poland after the signing of the Munich Pact in 1938. Germany occupied Polish Silesia from 1939 to 1945, and after World War II Poland annexed most of German Silesia. Upper Silesia, in southern Poland, is an important industrialized area.